Vehicle/deer collisions (“DVC”) are a quite serious danger to drivers (and animals), comprising as much as 4% of all US vehicular collisions and causing many fatalities yearly. In certain parts of the country, such as rural areas (and increasingly in suburban areas as well) the frequency of such collisions has increased markedly in the modern era. This might be due to the combination of effective environmental protection and the absence of effective predation (as most natural predators are now absent while human hunting takes a very small percentage of deer populations).
For those living in urban areas, this may sound trivial, however a few numbers may help explain the seriousness of this.
In 2010 in the state of Michigan alone, there were 55,867 reported accidents between vehicles and deer. The average insurance claim for deer vehicle damage ran $2,100 US. More importantly 11 people died in these DVC accidents in this one state alone.
In the USA alone, 247,000 deer/vehicle collisions occurred in 2010, resulting in over one BILLION dollars (US) in damage, and over 200 human fatalities. The high death toll may be partially due to the fact that a deer's center of mass is quite high off of the ground and the body does not behave the same as a human body does when hit by a vehicle at high speed. In a collision, the animal's legs are quickly broken, leaving the mauled 200+ pound carcass to roll across the hood of the vehicle and smash through the windshield into the passengers. Outcomes are obviously even worse if the animal is caught in the act of leaping or if the vehicle is a motorcycle.
Several billion more US dollars are spent every year in an effort to reduce these accidents. (Common measures include signage, fencing, and so on). Yet the result is a huge and ongoing toll of death and destruction from a type of accident so mundane and ordinary that it rarely gets any serious attention.
All of these statistics are for the United States only, but in fact the same problem occurs and the same sorts of measures are taken, virtually world-wide, on continents including at least South America, Asia and Europe. For example, the White-Tailed Deer alone ranges from Canada through the US (from the Rockies eastward), through Mexico, Central America and across most of South America, and this is merely a single species of the many species of deer worldwide.
Drivers, fleet operators and insurance companies can take vehicle based measures to attempt to prevent DVCs.
A vehicular safety deer whistle is a small air driven whistle installed on the exterior of a vehicle in a location and orientation such that when the vehicle is in motion (often at a speed above some minimum required in order to drive the whistle) a shrill noise is produced at a frequency not audible to human beings but clearly audible to deer. In general, the whistle is mounted on the exterior of the vehicle, so the air passing over the vehicle drives the whistle. Some air enters the mouth of the whistle bore or whistle cavity. Inside of the bore, the air is partially split into two streams, one of which passes through cleanly while the other stream swirls in accordance with the shape of the whistle cavity, “packing” and “unpacking” inside the cavity over and over again. Since an extremely high pitch (high frequency, thousands of hertz in this case) is desired for a deer whistle, extremely rapid packing and unpacking is desirable and so small cavities/bores and small divisions of the air stream are also desirable. In point of fact, the interior of the applicant's product bears a passing resemblance to the interior of an organ pipe, however, huge organ pipes are used to produce the low tones used in organ music while the present invention uses a tiny “organ pipe” in attaining sounds too highly pitched for human hearing. Both simply resonate at a frequency determined by size and geometry.
While the theory of the deer whistle is sound, the results of independent testing have been mixed. In some cases the whistles are found to perform well, while in other cases no useful effect is found.
An example of one of the few independent tests to prove the utility and efficiency of deer whistles is that testing carried out by the Modoc County, Calif., Road Department and Public Works Department.
In that test 1,648 vehicles were equipped with one of three different types of deer whistle (including the precursor to the present invention) and driven for an extended period of time. A control group of vehicles were tracked but did not receive deer whistles. During the testing time frame, the control group had numerous DVC accidents, while for the whistle equipped group of vehicles the expected number of DVCs would have been 5.7, however in fact there were zero DVC in the whistle equipped group, leading the study authors to conclude with 99.3% certainty (chi-squared of 7.2) that the deer whistles worked. The three types of deer whistles used included an electronic whistle as well.
The authors compared costs of the study program versus damage costs for 5.7 accidents and found the cost benefit ratio of deer whistles to be a favorable 2.7 to 1 in the study, indicating deer whistles to be an economically beneficial item.
However, this study is for several types of deer whistles, not a comparison between types. A more pointed study was carried out by the Business Research Group, which mounted deer whistles on vehicles in four counties in three different states and observed and quantified the reactions of visible deer to the whistle equipped vehicles, breaking the results down by type of whistle. Two types of whistles were tested, valve-type and flow-through type, four models of valve-type and five models of flow-through. The precursor of the present invention as used in the test was also a double-bore flow through whistle.
These results were fairly shocking Valve-type deer whistles were not found effective enough at moving deer to allow any measurement and quantification. Valve-type deer whistles will not be further discussed in this patent application.
Among types of flow-through whistles (the present invention is obviously a flow-through design), three models scored between 70% and 40% effectiveness at inducing a useful response from deer, that is, at causing the deer to move away at the proper time. Only two models of whistle (the precursor to the present invention being one of these two) were able to attain an effectiveness above 90%.
(These test results and supporting data may be found at the following website address: http://www.deerwhistle.com/html/research comments.html, and for this application were accessed on Dec. 27, 2011. The various tests have various authors and were undertaken by the organizations (Modoc County and Business Research Group) identified previously.)
Clearly, deer whistles vary enormously in effectiveness, not just based upon type but also based upon other factors which might be harder to quantify.
One possible solution to this problem is of course to provide more than a single whistle bore through the whistle. Indeed, common types of whistles are sold in pairs, possibly so as to provide a higher degree of reliability. The precursor to the present invention and the “Screaming Hawk” brand of whistle both take this a step further by providing two bores in a single whistle housing.
One explanation for the lack of testing success found in brands other than that of the applicant may be the issue of production quality. In general, most deer whistles of competing companies tend to be cheaply produced and of irregular quality. However, the production of sound is sensitive to extremely small variations in the geometry of the whistle, so slight manufacturing irregularities can result in deer whistles which appear to the naked eye to be identical to other, working, deer whistles, but which do not produce noise, or produce weak noise, produce noise only under a few limited conditions of speed, and so on and so forth. Even a few thousandths of an inch in difference can render a whistle mute, and most cheaply constructed deer whistles can easily exceed these tolerances.
As will be discussed below, the applicant had production level testing done to determine how manufacturing might be conducted to create reliable deer whistles.